Apparatus for twisting and plying strands



March 10, 1970 A. w. VIABBER nmnmus FOR 'I'WIS'I'ING ma FLYING swamps 5 Sheets-Sheet 1 Filed Sept. 10, 1968 INVENTOR WW March 10, 1970 A. w. VIBBER 3,499,277

APPARATUS oR TWISTING AND FLYING STRANDS Filed Sept. 10, 1968 5 Sheets-Sheet 2 I II K J y g INVENTOR WA). dmgw March 10, 1970 A. w. VIBBER 3,

APPARATUS FOR TWISTING AND FLYING STRANDS Filed Sept. 10, 1968 5 Sheets-Shet 5 T1 4- b I -S.

a c I 1 F 1 97 /59 I i a 65 J I E I I. l mmlL 50 i -L W! 4 95 INVENTOR M4 W U March 10, 1970 Ai-w. VIBBER APPARATUS FOR TWISTING AND FLYING STRANDS 5 Sheets-Sheet 4 Filed Sept. 10, 1968 INVENTOR W A). 0%

A. vW. VIBBER MPARATUS FOR TWISI'ING AND FLYING STRANDS March 10, 1970 5 Sheets- Sheet 5 Filed Sept. 10, 1968 Wmdwh United States Patent O 3,499,277 APPARATUS FOR TWISTING AND PLYING STRANDS Alfred W. Vibber, 560 Riverside Drive, New York, N.Y. 10027 Continuation-impart of applications Ser. No. 635,013, May 1, 1967, and Ser. N0. 685,996, Nov. 9, 1967. This application Sept. 10, 1968, Ser. No. 759,538

Claims priority, application Canada, June 6, 1967, 992,327; Jan. 26, 1968, 10,858 Int. Cl. D01h 7/90 U.S. Cl. 5758.3 34 Claims ABSTRACT OF THE DISCLOSURE A stranding machine of the skip type for twisting and plying strands. A loop or balloon of a second strand fed under tension from a source of supply, is rotated about a source of supply of a first strand, and the two strands are fed forward under tension at substantially constant speed to a plying point. The resulting plied strand or cord is pulled from the plying point by a variable speed take up capstan which is under the control of at least one tension sensitive means engaging a strand of the Singles strandplied strand system. In the illustrative embodiments, the one or more tension sensitive means are connected to one branch shaft of a differential gearing mechanism, the main shaft of which is driven at constant speed and the other branch shaft of which drives the variable speed take up capstan. The apparatus of the present invention may be advantageously employed in a system of the general type shown in Clarkson et al. Patent No. 3,108,427, wherein a plurality of outer singles strands are fed under tension from a common multiple supply beam to a plurality of similar ply-wrapping spindles of the skip type. In such system, the cords from the spindles are pulled therefrom, assembled in close parallel relationship, and are wound up on a common beam.

In accordance with one embodiment of the invention, three tension sensitive means, all connected to said one branch shaft of the differential gearing mechanism, are employed in the system: (1) between the source of the second strand and its feeding capstan, (2) between such feeding capstan and the balloon, and (3) between the variable speed capstan for the cord and the common take up beam. In other embodiments, a single tension sensitive means, engaging the second strand between its source and its feeding capstan, is employed.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of application Ser. No. 635,013, filed May 1, 1967, now abandoned, and of application Ser. No. 685,996, filed Nov. 9, 1967, now abandoned.

BACKGROUND OF THE INVENTION Field of the invention The invention relates to an apparatus for plying together two strands without adding to the twist of either. Such apparatus is of the so-called skip stranding type wherein a loop of one strand is rotated about a source of supply of another strand, the two strands being fed to a plying point and being taken up under tension from the plying point.

Description of the prior art This invention relates to an improvement over applicants Patent No. 3,295,304, the embodiments shown herein specifically being of the general type illustrated in 3,499,277 Patented Mar. 10, 1970 FIGS. 5 and 6 of such patent. In FIGS. 5 and 6 of Patent No. 3,295,304, the tension sensitive roller 22 is solely engaged and retarded by the singles strand b which passes partially about it.

SUMMARY OF THE INVENTION The invention relates to a stranding machine of the skip type, of the same type as those disclosed in the above Patent No. 3,295,304, for twisting and plying cords, and more particularly relates to the control of balloon size and/ or tension by detecting variations in the tension of the outer, ballooned strand in advance of the balloon and employing such variations in the tension to control the speed and/ or tension under which the resulting cord is removed from the plying point. In the apparatus of the present invention, such control for the means which removes cord from the plying point is more positive than that of such patent, and in certain of the embodiments disclosed herein is of simplified, more economical construction.

Although the apparatus of Patent No. 3,295,304 works well, should the singles strand b break in the zone thereof passing over roller 122, the variable speed take up capstan 54 would lose its control. In accordance with the present invention, the tension sensitive member, which engages a zone of the outer singles strand in its passage toward the plying point, is yieldingly driven by a constant speed rotatable driving means at a speed which is different from but relatively close to the speed at which the outer singles strand tends to drive the tension sensitive member. The character of the drive between the constant speed rotatable means and the tension sensitive member or the shaft mounting such member is such as to permit variations in speed of rotation in the tension sensitive means upon variations in the tension in the zone of the outer singles strand which it engages. At the same time, such yielding drive of the tension sensitive member by the rotatable driving means maintains the tension sensitive member under constant, stable control even if the outer singles strand should break. Such yielding driving of the tension sensitive member also facilitates the starting up and shutting down of the spindle, since the constant speed rotatable means tends to drive the variable speed take up capstan at all times at a speed which is close to that at which it rotates when the apparatus is in normal stable operation.

In first, third, and fourth disclosed embodiments of the invention, shown in FIGS. l-3, inclusive, FIGS. 6, 7, and 8, and FIG. 9, respectively, the tension sensitive membet and the constant speed rotatable means are located on fixed centers, the yielding drive between them, which is frictional, remaining constant despite variations in the tension of the outer singles strand engaging the tension sensitive member. In the second illustrative embodiment, shown in FIGS. 4 and 5, the constant speed rotatable means is mounted on a fixed axis, and the tension sensitive member is mounted so as to be free to move a short distance toward and away from the rotatable means. The tension sensitive member diverts the outer singles strand into a salient zone which converges in a direction opposite the constant speed rotatable means. As a result, changes in tension in the zone of the outer singles strand which engages the tension sensitive member not only vary the speed of rotation of the tension sensitive member by reason of (1) changes in engagement thereof by the strand, but also vary (2) the torque transmitted to the tension sensitive member by the constant speed rotatable means. Effects (1) and (2) are additive, and so the second embodiment is somewhat more positive in its control of the balloon than the first embodiment.

Another feature of the invention, which is particularly disclosed in connection with the embodiments of FIGS.

4 and FIGS. 6 and 7; FIG. 8; and FIG. 9 is the provision of a system wherein only one tension sensitive means is employed, such tension sensitive mechanism engaging the outer singles strand in the zone thereof extending from its source of supply to the feeding capstan therefor. Such embodiment is simpler than the other disclosed embodiments; it may advantageously be employed, for example, in a multiple supply beam to multiple take up beam system. The tension sensitive means, the variable speed take up capstans, and the gearing mechanisms which drive the cord removing means under the control of the respective tension sensitive means may be disposed at various places in the system consistent with the above limitations. Thus all of such parts, if desired, may be placed in the section of a multiple spindle frame containing both.the supply beam for the outer singles strands and the take up beam for the plied strands or cords.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a somewhat schematic view in elevation of a strand plying spindle in accordance with a first with a first embodiment of the invention, common supply and take up beams for the outer singles strand and cord, respectively, being shown, certain of the parts being shown in section;

FIG. 2 is a fragmentary view in horizontal section through a portion of the spindle of FIG. 1 at the location of the composite outer capstan thereof and the means for controlling the speed of the variable speed cord take up capstan portion thereof, certain of the parts being shown in plan and others in horizontal section, the section being taken along the broken line 22 of FIG. 1;

FIG. 3 is a fragmentary view in vertical section through the composite capstan and control thereof, the section being taken along the line 33 of FIG. 2;

FIG. 4 is a fragmentary view in side elevation Of the portion of a second embodiment of strand plying spindle in accordance with the invention, the view showing the composite .outer capstan of the spindle and the mechanism for controlling the variable speed cord take upon portion thereof;

. FIG. 5 is a view in vertical section through the mechanism of FIG. 4, the section being taken along the broken section line 55 of FIG. 4, certain of the parts being shown in elevation;

FIG. 6 is a view similar to FIG. 1 of a third embodiment of apparatus in accordance with the invention;

FIG. 7 is a fragmentary view in horizontal section through a portion of the spindle of FIG. 6, the section being taken along the broken line 77 of FIG. 6;

FIG. 8 is a schematic view of a fourth embodiment of apparatus in accordance with the invention, such apparatus having common supply and take up beams thereof disposed at the warper end of the frame, the means for controlling the speed and tension of pulling of each of the cords from its plying point being located at such warper end of the frame; and

FIG. 9 is a schematic view of a fifth embodiment of apparatus in accordance with the invention, such apparatus being similar to that of FIG. 8 with the exception that an auxiliary flyer is employed in the spindle assemblies of FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As is apparent from the above, five embodiments of strand plying spindle in accordance with the invention are shown herein. The first of such embodiments is shown in FIGS. 1, 2, and 3, wherein the outer singles strand for the spindle is shown as being provided by a common supply beam and the cord produced by the spindle is shown as being taken up by a common take up beam. In such embodiment not only does the tension of the outer singles strand in the rotating loop control the speed of take up of the cord from the plying point, but variations in the tension of the run of the singles strand from the supply beam to the spindle and variations in the tension of the cord between the variable speed take up capstan therefor and the common take up beam also function to control the speed of the variable speed cord take up capstan. In the second embodiment, shown in FIGS. 4 and 5, the outer singles strand is shown as being supplied by an individual package and the cord produced by the spindle is shown as being taken up on an individual package or bobbin. The third embodiment, shown in FIGS. 6, 7, and 8, differs from that of the first embodiment in that the auxiliary flyer of the first embodiment is omitted, and that a single tension sensitive means, connected to the said one branch shaft of the differential gearing mechanism, is employed. Such single tension sensitive means engages the outer singles strand between its source of supply and the capstan which feeds it toward the balloon or rotating loop the the spindle. In the fourth embodiment of FIG. 8 and the fifth embodiment of FIG. 9 the means for controlling the speed and tension of pulling of each of the cords from its plying point are located at the warper end of the frame.

The embodiment of spindle shown in FIGS. 1, 2, and 3 is designated generally by the reference character 10. Such spindle has a main vertical hollow shaft 11 which is supported for rotation in suitable bearings mounted on the frame 14 of the apparatus, the upper such bearing being covered by a bearing housing 12. The shaft 11 is rotatably driven by suitable means, that shown including a pulley 15 affixed to the shaft 11 and a belt 16 entrained over the pulley. The belt 16 in this instance is driven by a suitable prime mover such as an electric motor (not shown). 7

Fixedly mounted upon the shaft 11 somewhat above the bearing housing 12 is a flyer in the form of a disc 17, such flyer rotating a loop 42 of the outer singles strand a about a source of supply 22 of a second, inner singles strand within the loop. A platform 19 is mounted upon the upper end of the shaft 11 by suitable bearings (not shown), the platform being held from rotation by the coaction of a first inner set of magnets 20 on platform 19 and a second outer fixed set of magnets 21, the magnets being spaced to provide a suitable annular gap between them through which the lower portion of the rotating loop passes. The inner singles strand b is supplied by an inner strand supply package 22 which is mounted upon the platform 19, the strand b from package 22 proceeding over suitable guides to a capstan 24 which is driven at constant speed through suitable gearing by the shaft 11. The supply package 22 is'disposed in a suitable protective enclosure or can 25 which is provided with a cover 26 serving to support an auxiliary flyer 44, to be described.

The outer singles strand a is shown being supplied by a common supply beam 27, such beam containing a plurality of strands wound in side by side relationship so as to supply outer singles strands to each of the plurality of plying spindles of a frame. Upon leaving the supply beam 27 the strand a passes through a conventional tensioning device, schematically shown at 29, for imposing a constant retarding tension upon the strand. Strand a then passes over a fixed guide roller 69 to an adjustable guide roller *68, thence into a first engagement with a first zone 38 of roller 28, and then to the portion of the lower or outer composite capstan 30 which feeds it forwardly at constant speed into the rotating loop or balloon 42 of the spindle. Adjustment of the guide roller 68 permits the angle of lap of the strand a about zone 38 of roller 28 to be varied. Roller 28 is connected to control the speed of the portion of the capstan 30 which feeds the cord from the plying point P of the spindle in such manner as to maintain the tension of the loop 42, and thus its diameter, within desired limits.

Upon leaving the capstan 30, the strand a engages the zone 31 of the tension sensitive member 28, and then passes to a guiding roll 32 which is adjustably mounted as indicated so as to vary the angle of lap of the strand a at itsengagement with such zone 31 of the tension sensitive member 28. The part 31 of roll 28 has a diameter which somewhat exceeds that of part 38. The strand a passes upwardly from roller 32 to an upper fixed roller 34 and thence laterally to a further guide roller 35, the right-hand exit surface of which is positioned coaxially of the upper apex guide for the loop 42. Roller 35 is mounted on a bracket 46 which is secured to an overarm 37 on a vertical standard 39 aflixed to the frame 14. The apex guide is provided by a tube 40 which is threadedly mounted in an opening in the overarm 37, the tube 40 being adjustable as to its vertical position. The lower end of the bore in the tube 40 is rounded in vertical axial planes to provide an apex guide 41.

Upon leaving the apex guide 41, the strand a, which is now rotated in a loop by the fiyer 17, travels downwardly to a strand guiding eye 46 provided in the outer end of an arm 45 on the auxiliary fiyer 44. The auxiliary fiyer 44 has a body 47 which is mounted on a suitable bearing in a housing 49 secured to the lid 26 of the enclosure 25 for the inner strand package. Upon leaving the eye 46 of the auxiliary fiyer, the rotating strand a travels downwardly about the enclosure 25 through the gap between the magnets 20, 21 and into a guiding eye 50 in the flyer 17. From eye 50 the strand a travels generally radially inwardly through an opening in the wall of the hollow shaft 11 to the plying point P, where it meet the inner singles strand b after the latter has been engaged and metered by the capstan 24 and has then been fed upwardly into the upper end of the bore in the main hollow shaft 11.

At the plying point P the two singles strands a and b are plied or wrapped about each other to form a cord c which then travels downwardly within the bore in the main shaft 11. Upon emerging from the lower end of the shaft 11 the cord travels in sequence about the two lower fixed guiding rollers 51 and 52 and then travels upwardly to the cord feeding portion of the composite outer capstan 30. Upon leaving the cord feeding portion of the capstan 30, the cord travels partially about a third, smallest diametered zone 33 of the tension sensitive member 28 and thence to a guide roller 54 which, as schematically shown in FIG. 1, is mounted for adjustment about the axis of the member 28 whereby to adjust the degree of lap of the cord about the zone 33 of the tension sensitive member. From roller 54 the cord travels to the common take up beam 55 which is driven, by means not shown, so as to wind the cord upon the beam at a substantially constant linear speed.

The construction and manner of operation of the composite capstan 30 and of the means for controlling the speed of the cord feeding parts thereof will be more readily apparent upon considering FIGS. 2 and 3. As there shown, the frame 14 of the apparatus includes a vertically disposed and horizontally elongated iron plate 56 and a similar rear plate 57 parallel to and spaced from plate 56. Plates 56 and 57 are connected together by suitable cross brace members 59, of which two are shown. For convenience, the means for driving the capstan 30 is mainly located within the space thus provided between plates 56 and 57 and cross braces 59.

A worm gear 60 is afiixed to the main spindle shaft 11 so as to rotate therewith, the gear 60 being shown disposed between bearings in the frame journalling the shaft 11. Meshing with the worm so as to be constantly driven thereby is a worm gear 61 which is fixedly connected to a hollow shaft or sleeve 62 which extends horizontally into the frame 14 and is journalled in the front plate 56 by a bearing 64. The end of shaft 62 which extends outwardly through the plate 56 has a capstan roll 65 fixedly connected thereto. Capstan roll 65 and a similar idle roll which is mounted on plate 56 and spaced somewhat from roll 65 form the metering portion of the capstan 30 for feeding the outer singles strand at substantially constant speed toward the balloon.

The portion of the capstan 30 which feeds the cord away from the plying point at variable speed is made up of a driven capstan roll 71 and an idle capstan roll 73 which is parallel to but spaced somewhat from the capstan roll 71. The roll 71 is fixedly mounted upon a shaft 72 which extends inwardly through the hollow shaft 62 and is driven in a manner to be explained. The idle roll 73 is mounted upon a shaft 78 coaxial of the idle roll 66 but unconnected thereto, that is, rolls 66 and 73 rotate freely with respect to each other. As shown, the singles strand a and the cord 0 pass in multiple spaced wraps around their respective capstan rolls 65, 66 and 71, 73.

The inner end of the shaft 72 which drives the capstan roll 7.1 passes freely through the frame 77 of a differential gearing mechanism 76 and is fixedly connected to a first bevelled gear 79 thereof. The frame 77 is connected to the inner end of the shaft 62 so as to rotate at constant speed therewith. A second bevel gear 80, opposing gear 79, is fixedly connected to a shaft 84 which is journalled in the frame 77 of the differential mechanism. The rear end of shaft 84 is journalled in a suitable bearing in frame member 57. Gears 79 and 80 are connected by two opposing idle bevel gears 81 and 82 which are journalled on the frame 77 of the differential gearing mechanism.

Fixedly connected to the shaft 84 is a spur gear 85 which meshes witha spur gear 86 which is fixedly connected to a cross shaft 87. Shaft 87 extends between and is suitable journalled in the plates 56 and 57 of the frame 14. The tension sensitive roll 28 is fixedly connected to the end of the shaft 87 which projects outwardly beyond the plate 56. The roll 28 is thus drivingly connected to the roll 71 of the cord feeding capstan 71, 73 through the differential gearing mechanism 76. The relative diameters of the parts 38, 31, 33 of roll 28, of rolls 65 and 71, and the pitch diameters of the gears 85, 86 are such that under normal stable operating conditions of the spindle the singles strand a in the zone thereof engaging the part 31 of roll 28 travels toward the plying point P at a speed which is slightly less than the surface speed of such part 31 When the tension in the strand a in the loop or balloon increases, such strand engages part 31 more forcibly in the zone 67 in which it engages it and thus tends to slow down the roll 28. By reason of the interposi ion of the differential gearing mechanism 76' in the drive train between the roll 28 and the roll 71, a decrease in the speed of rotation of roll 28 produces an increase in the speed of rotation of the roll 71, thereby pulling the formed cord c under greater tension and at a greater speed from the plying point. Upon a decrease of tension in the strand a in the loop or balloon, the speed of rotation of roll 71 decreases, thereby subjecting the formed cord 0 to less tension and pulling it from the plying point at a lower speed. As a result, the diameter of the loop or balloon is maintained within desired limits.

In the system shown wherein the strand a is supplied by a common supply beam 27 and the cord is taken up on a common take up beam 55, two other tension effects in the system are imposed upon the roll 28 whereby to maintain tensions in the entire strand system in balance. The first such additional effects is produced by leading the strand a from the guide roll 68 into engagement with part 38 of roll 28 in the passage of such strand into initial engagement with the roll 65 of capstan 10. In the embodiment shown the zone of such engagement, designated 70 (FIG. 2), subtends an angle which it appreciably less than the angle substended by the zone 67 of engagement of the run of strand a leaving roll 65 with part 31 of roll 28. The tension in the zone 70 may be, for example, on the order of g. and that in zone 67 may be, for example, on the order of 450 g. The actions resulting from the engagement of strand a with part 38 of roll 28 in zone 70 and with part 31 in zone 67 are additive. Part 38 of roll 28 is of such diameter that its surface speed, in normal operation, is slightly greater than the linear speed of strand a; the surface speed of part 38 of roll 28 is also greater than the linear speed of strand 0. The effect from such engagement of part 31 by the zone 67 of the strand a far outweighs that from engagement of part 38 by the zone 31 of such strand. It will be seen that an increase in tension in zone 70 of strand a tends to cause roll 28 to rotate more slowly, whereby to rotate roll 71 faster, whereas a decrease in tension of strand a in such zone tends to cause roll 71 to rotate at a slower speed.

The second additional effect upon the roll 28 is that caused by engagement between the run 75 of the cord leaving the capstan 71, 73 with the portion 33 of the roll 28. Such last zone of engagement in the embodiment shown subtends an angle somewhat smaller than that subtended by zone 67 of strand a, but acts upon a member 33 which is of somewhat smaller diameter than member 31. The angle substended by such zone of engagement, which may be adjusted by adjusting guide roll 54, and the diameter of part 33 of roll 28 are so chosen as to be properly correlated with other parts of the system, the diameter of part 33 of roll 28 being such that in the normal operation of the apparatus the surface speed or part 33 somewhat exceeds the linear speed of the cord 0 in the zone 75 thereof. The tension in the cord 0 in zone 75 may be, for example, 100 g. It will be seen that when the tension in zone 75 of the cord 0 increases, the cord engages part 33 more forcibly, thus tending to slow the roll 28 and thereby tending to drive roll 71 at a higher speed. When the tension in zone 75 decreases, the speed of roll 71 decreases.

In accordance with the invention, the roll 28 is yieldingly driven by a constant speed rotatable means which tends to drive the roll 28 at a speed such that the surface speed of its part 31 slightly exceeds the normal speed of the strand a passing over such part 31. Thus, by Way of example only, in a system wherein the cord c is taken up at a mean relative speed of 100, the strand a is fed at a mean relative speed of 114, the difference between such relative speeds being caused by the loss in effective length of each of the singles strands a and b in wrapping them about each other to form the cord 0. Under such conditions the constant speed rotatable means, for example, would per se tend to drive roll 28 so that part 31 thereof had a surface speed of 116. The actual surface speed of part 31 at any given time during stable operation of the apparatus lies between the relative values 114 and 116, being for example 115.

In the embodiment shown, the constant speed rotatable means is provided by an annular resilient member 89 made of rubber or the like mounted on roll as by being snapped into a groove therein so as to rotate synchronously with roll 65. Member 89 firmly engages an annular zone 90 on part 31 of roll 28. As above indicated, the relative diameters of the outer surface of member 89 and the diameter of surface 90 are such that the means 65, 89, 90 tend to rotate the roll 28 so that the surface speed of part 31 thereof slightly exceeds the speed at which such part tends to be rotated by the strand a passing thereover.

The thus provided yielding drive between roll 65. and roll 28 is such as to maintain the roll 28 under substantial control at all times while permitting such roll to be varied in speed, and thus the speed of capstan roll 71 to be varied, upon changes in the tension in the zones 67 and of strand a and of the cord in zone thereof. Should the strand a break, the roll 28 will then be driven so that the part 31 thereof has a relative surface speed of substantially 116, there-by continuing to drive the capstan roll 71 until the apparatus is brought to a stop. At all times, in stable operation of the apparatus, the speed of rotation of the roll 28 is such that the surface speed of part 31 thereof lies between the speed of strand a at zone 67 and the speed with which portion 31 of roll 28 tends to be driven by the yielding constant speed drive means 65, 89, 90.

The second embodiment of strand plying apparatus in accordance with the invention, which is shown in FIGS. 4 and 5, is generally designated by the reference character 94. In such embodiment the outer singles strand a is supplied by an individual package from which it travels through a constant tension retarding means, schematically shown at 98, and thence in a run 112 to a first larger diametered roll 124 of a composite roll 114 forming part of an outer composite capstan 110. After passing repeatedly in runs about the roll 124 and an idle roll 118 spaced therefrom, the strand a leaves the roll 118 and travels in a run 117 upwardly to a tension sensitive roll 116 about which it extends throughout a zone 150. Upon leaving the tension sensitive roll 116, strand a travels downwardly in a run 119 to an adjustable guide roll 120 and thence to another guide roll 121 from which it rises in a run 122 to travel toward the rotating loop or balloon. The path of travel of the strand a and the instrumentalities acting thereon in advance of the plying point P are the same as those in FIG. 1. After travelling inwardly from the guide eye in the fiyer, the strand a meets an inner strand b which is supplied and fed to the plying point in the same manner as in the apparatus of FIG. 1.

The resulting cord 0 travels downwardly through the bore in the central hollow spindle shaft 97, thence partially around guide rollers 106 and 107 to rise in a run 109 extending to a smaller diametered roll of the composite capstan 110. A roll 123 mounted on shaft 113 coaxial of and afiixed to the roll 118 is spaced from the roll 125. The cord c travels in multiple wraps about the rolls 125, 123 and then passes in a run 111 to a take up bobbin 96, as shown. Because the outer singles strand a is supplied from an individual package 95 and because the idle roll parts 118, 123 are connected to rotate in synchronism, no further control of the system is necessary except for that provided by variations in the speed of rotation of the tension sensitive roller 116 caused by variations in the tension in the strand a at the zone 150 thereof.

The frame of the apparatus, which is generally designated 99, is made up of a front plate 100, a rear plate 101, upper and lower plates 102, 104, and suitable cross bracing members, not specifically shown. The hollow spindle shaft 97 is journalled in suitable bearings of the frame, of which one is shown at 105. A worm is fixedly connected to shaft 97 within the hollow frame, gear 130 meshing with a worm gear 131 which is affixed to a hollow shaft 126 journalled in frame member 100 in a bearing 127. Affixed to the outer end of shaft 126 is the above mentioned capstan roll 124 which forms a part of the metering capstan for the outer singles strand a. The inner rear end of the hollow shaft 126 is fixedly connected to the frame of a differential gearing mechanism so that such frame rotates with the shaft. The smaller capstan roll 125 of the roll set 114 is mounted upon the outer end of a shaft 132 which extends within the shaft 126 for rotation with respect thereto, the rear end of shaft 132 being fixedly connected to a first bevel gear 136 of the differential gearing mechanism 134. An opposing similar bevel gear 137 is fixedly connected to a shaft 141 which at its rear end is journalled in a suitable bearing 129 in the plate 101. Affixed to the shaft 141 is a first spur gear 142 which meshes with a second spur gear 104 affixed to a cross shaft 145. Shaft is journalled at its rear end in a bearing 149 mounted in the plate 101. The outer race of the bearing 149 and the teeth of gears 142 and 144 are of such contour as to permit a limited rocking of the shaft 145 in the plane of the paper of FIG. 5 while maintaining driving relationship between the shafts 141 and 145.

The forward end of shaft 145 is mounted in a bearing 146, the outer race of which is aflixed to a slide 147. Slide 147 is mounted in a vertical window in plate 100 with forward and rear flanges on the slide overlying the edges of the window and the window of somewhat greater vertical length than the slide whereby the slide is permitted a limited movement in a vertical direction. A yielding constant speed drive is provided between the roll 124 and the roll 116 and shaft 145 by a resilient rubber or rubber-like ring member 151 which is secured to the roll 116 so as to rotate therewith. The outer surface of the member 151 bears upon an annular zone 153 of roll 124, the relative diameters of roll 124, member 151, and zone 153 being such that the roll 124, acting through parts 151 and 153, tends to drive the roll116 with a surface speed which is substantially the same as the linear speed of the strand a engaging roll 116 at zone 150. During normal stable operation of the system the actual surface speed of roll 116 somewhat exceeds the linear speed of the strand a and the speed at which roll 11-6 tends to be driven by the constant speed rotatable means 151, 153. Thus both the strand a in zone 150 thereof and the driving means 124, 151, and 153 tend to act to retard the rotation of the roll 116.

The force with which member 151 is initially pressed against the zone 153 is adjustable. Thus a coil compression spring 155 is mounted upon the upper end of the slide 147, the coil spring being adjustable compressed by a screw 156 threaded into the upper horizontal end portion of an extension of the plate 100. The screw 156 is readily adjusted by turning the head 159 thereof, and is held in adjusted position by a lock nut 157.

As shown, the runs 117 and 119 of the strand a approaching and leaving the roll 116, respectively, form a salient zone which converges upwardly and in the direction opposite the roll 124. Consequently, increased tension in the strand a in the zone thereof including zone 150 and runs 117 and 119 causes the runs 117 and 119 to pull the roll 116 downwardly more forcibly, whereby the member 151 engages the zone 153 more forcibly thus to retard the rotation of the roll 116 so that its surface speed more nearly equals the surface speed of the roll 124.

In the embodiment shown, the idle rolls 118 and 123 are integrally connected so that they also function to maintain the strand system stable. Thus an increased tension in the run 111 of the cord causes the cord to engage roll 123 more forcibly and thus tends, through roll 118, to drive the singles strand a so that the capstan 110 delivers the singles strand at an increased rate. The converse is true as to a decrease in tension in the run 111 of the cord c, the capstan 110 then delivering the singles strand a at a decreased rate. On the other hand, when the tension of the strand a in the balloon increases, that is, balloon diameter increases, the strand a engages the roll 118 more forcibly, thereby to cause the roll 123 to rotate faster and to tend to pull the cord from the plying point under an increased tension and at a faster speed. Should, however, the balloon decrease in diameter and its tension decrease, the strand a has a smaller driving effect upon roll 118 and thus upon roll 123. Under such condition, the speed of pulling of the cord from the plying point by the roll 123 is then decreased.

In the above described embodiments of 1) FIGS 1, 2,

and 3, and (2) FIGS. 4 and 5, the presence of the auxiliary fiyer 44 with its eye positioned further radially outwardly than the eye 50 on the fiyer disc causes the plying point P to be non-self-compensating. In the embodiment of FIGS. 6 and 7, however, no auxiliary fiyer is employed. The plying point P is self-compensating, because the fiyer 17 of the spindle engages the balloon 'below the bulge of the latter. Thus as the diameter of the balloon increases, with a ballooning strand of constant Weight per unit length (denier), the tension in the balloon decreases, and and such diameter decreases the tension in the balloon increases. More of the outer strand (1 is absorbed into the cord when the tension in strand a is less than that of the inner singles strand b, and less of the outer strand a is absorbed into the cord when the tension in strand a is 10 higher than that of the inner strand b. Thus the action at the plying point P tends to maintain the baloon diameter within desired limits.

In the embodiment of FIGS. 6 and 7, parts which are the same as those of FIGS. 1, 2, and 3 are designated by the same reference characters. The embodiment of FIGS. 6 and 7 differs from that of FIGS. 1, 2, and 3, in the following main features: 7

As noted, no auxiliary fiyer is employed in the embodiment of FIGS. 6 and 7.

The upper or inner singles strand feeding capstan is made to engage its strand b somewhat more positively than the outer or lower capstan 65, 66 engages singles strand a. For this purpose the capstan 24 is provided with a presser roll 146 which is spring biased toward the driven roll 144 of the capstan. The multiple loops of strand from the bottom of roll 145 to the presser roll, 145 are thus thrust against the surface of roll 144 by the presser roll. It may sometimes be desired that the strand b be even more positively engaged by the capstan 144, 145. This can be effected by running the last span of the strand from the bottom of roll 145 to the presser roll, partially around the presser roll, and thence upwardly above roll 144 to the upper end of the hollow main shaft of the spindle.

The single tension sensitive means employed in the illustrative system is the surface of the circular cylindrical roll 38, which is engaged by the run of strand a approach ing the capstan roll 65 after it has passed through the constant tension device 129. It will be assumed that device 129 engages in the same manner all of the singles strands a of a plurality of similar spindles of the ply-wrapping type. If one of such strands should be held under unduly. high tension at the run thereof engaging roll 38, it will tend to increase the speed of roll 38, since, as in the first embodiment, the diameter of roll 38 is such that its surface speed, in normal operation, is less than the linear speed of strand a. This causes the speed of the branch shaft 72 of thediiferential gearing mechanism to decrease, and thus the capstan 71, 73 to pull the cord 0 less forcibly and more slowly. The reverse action takes place when the tension in the portion of strand a engaging roll 38 decreases.

The capstan 65, 66, which feeds the strand a toward the balloon, although causing the strand a to travel in substantial synchronism with the surface of capstan roll 65, permits a small degree of slippage of strand a with respect to roll 65. It should be pointed out that the portion of the strand a approaching the capstan 65, 66 is under a tension which is markedly less than that in the portion of such strand which extends between the capstan 65, 66 and the balloon. Thus the normal tendency of strand a is to travel toward the balloon at a speed which is at least slightly greater than the synchronous speed of capstan 65, 66. When the tension in the strand a at the zone thereof immediately in advance of the capstan increases, the rate of slippage of strand a toward the balloon decreases; this effect also tends to alleviate the unbalance of tensions in the singles strand-cord system.

The (1) run of cord c between the capstan 71, 73 and the take up beam is at a tension which is markedly lower than (2) that of the cord between the plying point and the capstan 71, 73. An unduly high tension in run (1) of the cord will tend to increase the speed of feeding of the cord by capstan 71, 73 by the direct addition of its increased forward pull upon the cord. The increase of tension in run (1) of the cord also tends to decrease the degree of slippage of the cord, in a direction which is toward the plying point, with respect to the capstan 71, 73.

In the embodiment shown, the common take up beam 155 is surface driven by one of the rollers 154, 167 upon which it is supported. A presser roll 175, which engages the top of the beam, strongly thrusts the wound cords on the beam into substantially non-slipping engagement 1 1 with rolls 154, 167. Roll 154 is driven with a predetermined constant torque by means such as a driven shaft 133 through the medium of a torque limiting drive device such as a slip clutch generally shown at 149. Alternatively, the roll 154 may be driven by an electric torque motor having a constant torque output.

The torque imposed upon roll 154 and thus upon beam 155 is opposed by all of the cords being wound upon the beam; as a result each cord tends to be pulled away from the capstan 71, 73 with a pull which, on the average, is the total driving torque imposed upon the beam 155 divided by the product of the instantaneous radius of the coils of cords on the beam times the number of cords being wound upon the beam. The described system tends to maintain the tension in run (1) of each of the cords close to such average tension. When the tension in such run (1) of a particular cord increases unduly, such increased tension tends directly to correct such condition by its pulling action upon the capstan 71, 73 as above described.

The capstan 71, 73 is also under the control of the tension sensitive roll 38 which engages the singles strand a after it has passed through the tensioning device 129. The angle of lap, that is, the length of zone 170, of strand a about roll 38 may be varied as required by appropriate adjustment of the adjustable guide roll 168, as indicated by the curved double headed arrow. An increased tension in the run of strand a in engagement with roll 38, as we have seen in connection with the first described embodiment, causes the differential gearing mechanism to drive capstan 71, 73 more slowly, and vice versa. This action opposes that on capstan 71, 73 by the run (1) of the cord. By a proper choice of the angle of lap of strand a about roll 38, however, the two opposing controls can be made such that the tension in the strand a in the zone thereof approaching capstan 65, 66, the tension in the cord approaching the capstan 71, 73, and the tension in the cord 0 in run 1) thereof can all be maintained within desirable limits.

The embodiment of FIGS. 6 and 7 may be modified by having the control of the tension in run 1) of cord 0 also contribute to the control of capstan 71, 73 through the differential gearing mechanism. This may be done by providingan extension similar to portion 33 (FIGS. 1 and 2) on tension sensitive roll 38, and passing the run (1) of cord 0 as it leaves the capstan 71, 73 into contact with such extension of the tension sensitive roll in the same manner as in FIGS. 1 and 2 wherein a zone 75 of cord 0 is shown engaging extension 33. In the embodiment now being described the take up beam will be disposed generally in the same location as the take up beam 55 in FIG. 1. With such construction, the capstan 71, 73 is under the joint control of two tension sensitive means, one engaged by strand a and the other engaged by cord 0, the two tension sensitive means being drivingly connected to the branch shaft 87 of the differential gearing mechanism.

In a further, non-illustrated embodiment, the apparatus of FIGS. 6 and 7 may be modified by omitting the tension sensitive roll 38 which engages strand a in such figures. The strand a is then led directly from tensioning device 129 to the surface of capstan roll 65. The roll 38 is, in effect, replaced by the tension sensitive roll 33 of FIGS. 1 and 2, roll 33 being engaged by the run (1) of cord 0 after the cord has left the underside of capstan roll 71 and is on its way to the take up beam. In this embodiment the take up beam will be disposed generally in the location of take up beam 55 in FIG. 1. This embodiment may be desirable, for reasons of economy and simplicity, where the strands a are of premium, highly uniform quality, so that the self-compensating properties of the balloon and plying point insure satisfactory control of the system in the zone thereof from the supply beam, through the spindle, and to the cord take up capstan 71, 73.

Although the embodiment of apparatus shown in FIGS.

6 and 7 has the outer composite capstan and the tension sensitive roll 38' disposed at or adjacent and driven by the main shaft of the spindle, it is to be understood that, if desired, such parts may be disposed at any desired position along the spindle frame. Thus the composite take up capstan and the tension sensitive means, when the supply and take up beams are disposed at the warper end of the frame, may be located at or adjacent the same end of the frame. The capstan 65, 66 for feeding strand a toward the balloon may be disposed at and driven by the main shaft of the spindle, or it may be disposed spaced from the main shaft between the apex guide for the balloon and the tension sensitive roll 38', as schematically shown in FIG. 8, and may be driven by an appropriate constant speed.

An arrangement of this type is schematically indicated in FIG. 8, wherein a plurality of plying spindles 10 (three shown) located in a spindle area 200 receive the outer singles strand a from and deliver the resulting cord c to the right-hand end of the frame. It is to be understood that, in a typical commercial frame for making tire cord, there may be a sufiicient number of spindles 10 to supply all of the warp cords or plied strands for making tire fabric. The common supply beam 27 and the common take up beam are disposed at such one end of the frame in the so-called warper area 201. Also located in such zone are the common tensioning means 202 for the strand a disposed downstream of the supply beam 27 and a cord-guiding or eyeboard 204 disposed immediately upstream of the take up beam 155.

The means for driving the take up beam 155 and for laying the cords 0 upon such beam may, for example, that shown in FIGS. 8, 9, and 10 of applicants US. Patent No. 3,336,740. When employing such mechanism, the eyeboard is fixed, and the take up beam is reciprocated along its length for a short distance while being rotated to wind the cords thereupon. The means for rotatably driving the take up beam may be similar to that shown in FIG. 6 herein, whereby the aggregate of the cords C being wound upon the take up beam is subjected to a substantially constant tension.

Also disposed in the warper area 201 are a plurality of single end or cord take up assemblies, one for each of the spindles 10'. Each of the take up assemblies, as in the embodiment of FIGS. 6 and 7, is composed of a differential gearing mechanism 76 having a main or first shaft fixedly connected to the rotatable, gear-containing frame or housing of the differential mechanism. A first branchshaft 72 of the differential mechanism drives the cord-advancing capstan 71, 73, whereas the other branch shaft 87 of the differential mechanism is drivingly connected to the tension sensitive rotatable member 38.

The first or main shaft of each of the differential mechanisms 76 is driven at the same constant speed. In the embodiment schematically shown herein, an elongated worm 159 extends in proximity to a plurality of the differential gearing mechanisms 76, the main shaft 160 of each mechanism being drivingly connected to the worm 159 by a worm gear 161 meshing therewith.

In the embodiment of apparatus shown in FIG. 8, the tension sensitive roller 38 is driven by means 89, 90, and so forth, so that under normal stable operating conditions the roller 38 has a surface speed which is at least slightly below the linear speed of travel of the singles strand a. Simply by way of example, the strand a may have a linear speed of 114 linear units in a given time. The means 89, 90 tend yieldingly to drive the roll 38 with a surface speeds of 112, so that the actual surface speed of the roll 38 lies somewhere between 114 and 112, for example 113. It will thus be seen that with an increased tension in the singles strand a in the zone thereof engaging the tension sensitive roll 38, roll 38 will be driven faster by strand a. Because of the action of the differential gearing mechanism 76 under such condition, the cord take up capstan 71, 73 is then driven at a lower speed. When the tension in the strand a in the zone thereof engaging roll 38 decreases, on the other hand, roll 38 slows down and the capstan 71, 73 speeds up.

As we have seen, the outer singles feeding capstan 65, 66 is somewhat impositive inits feeding of strand a, the inner capstan 144, 145 feeding its inner strand b appreciably more positively. Because of the slip between the strand ;a and the driven roll of the capstan 65, 66, the strand a always travels through such capstan at a speed which somewhat exceeds the synchronous speed of the driven roll thereof. This follows because the strand a travels from a low tension zone engaging roll 38 in which it is subjected, for example, to 100 g. tension, to one on the other side of the capstan 65, 66 of markedly greater tension, such as 450 g., for example. The low tension zone of the strand a approaching the capstan 65, 66 acts variably to snub the strand a about the driven roll of such capstan.

When the tension in the strand a approaching and engaging capstan 65, 66 is high, the speed of the strand a forwardedtoward the balloon by the capstan is decreased, that is, it more nearly approaches the synchronous speed of the driven roll of such capstan. On the other hand, when the tension in the zone of'strand a approaching and engaging the capstan 65, 66 decreases, the strand a slips forwardly with respect to the capstan 65, 66 at a higher speed, and the balloon thu's tends to increase in diameter. Thus there is a predictable correlation between the variation in tension in the Zone of strand a engaging roll 38 and the diameter of the balloon.

Since the tension of the strand in the balloon decreases when the diameter of the balloon incerases, there is also a predictable correlation between the tension of the strand a in the low tension zone thereof engaging roll 38 and the tension of the strand in the balloon. The single end take up assembly, including the differential mechanism 76, the tension sensitive roller 38 engaging the strand a entering the balloon, and the variable speed capstan 71, 73, pulling the cord from the plying point, employ such relationships in controlling the speed of pulling of the cord from. its plying point so as to maintain the tensions in the entire strand system from the supply beam 27 to the take up beam 155 under stable control.

The embodiment of FIG. 9 differs in one respect from that of FIG. 8 in that the spindle assemblies 10" thereof are provided with auxiliary fiyers 205 which are similar to the auxiliary fiyers 44 of the first described embodiment. As we have seen, the use of such auxiliary fiyers renders the plying points of the spindle assemblies nonself-compensating. The control devices 76', however, function with the other elements of the system, including the impositive singles strand feeding means 65, 66, to maintain the diameter of, and the length of singles strand in, the balloon within desired limits, and the tension of the outer singles strands in the various Zones thereof etween the common outer singles strand supply beam 27 and the spindle assemblies, and the tension of the cords in the various zones thereof between. the plying points and the common take up beam 155 Within desired limits.

The control devices 76 are made similarly to that shown at 114, 115, 116 in FIGS. 4 and 5, so that they control and compensate for variations in balloon diameter in spindle assemblies wherein there are employed auxiliary fiyers having effective diameters somewhat greater than that of the driven main fiyer and the upper, short balloons formed between the apex guide and the auxiliary fiyers spin above the bulge. When the diameter of, or length of strand in, such balloons increases, the tension of the strand in the balloon increases. Such increase in tension in the ballooning strands is transmitted through the impositive strand feeding means 65, 66 to the zones of the respective strands engaged by the tension sensitive rolls 38, so that the branch shafts 87 of the devices 76 receive meaningful signals or responses which afford a means whereby the speed of and/or tension at which the respective cords are withdrawn from their plying points may be varied in such manner as to maintain the balloons and the strand-cord system under control.

The lengths of the cords between the plying points and the cord-pulling rolls 71, 73 may be subjected to the full force of the cord at the plying points, as in the embodiment shown in FIG. 9. In an unillustrated, modified embodiment of such apparatus, however, there may be employed a cord take up capstan upstream of the rolls 71, 73 of the control device 76', such take up capstan being of the construction described in lines 1-41, inclusive, of column 8 of my Patent No. 3,388,542. In such modified system, the tension of the cord in the zone thereof downstream of the cord take up capstan and upstream of the rolls 71, 73 of the control device 76 is markedly less than that which would have existed upstream of the rolls 71, 73 in the absence of the cord take up capstan. The tension of the cord immediately approaching the cord guide eyeboard 204, in the thus modified system, may then be on the same order as, or substantially equal to, that in the respective outer singles strand immediately downstream of the common tension device 202.

Although a limited number of embodiments of the invention have been illustrated in the accompanying drawings and described in the foregoing specification, it is to be especially understood that various changes, such as in the relative dimensions of the parts, materials used, and the like, as well as the suggested manner of use of the apparatus of the invention, may be made therein without departing from the spirit and scope of the invention, as will now be apparent to those skilled in the art. Thus although the differential gearing mechanism has been shown and described as being driven by the main shaft 11 of the spindle, it will be understood that it may, if desired, be driven by any other suitable source of power. Also, although the differential gearing mechanism is shown as being disposed adjacent its respective spindle, it is to be understood that it may be located remote from the spindle. This may be particularly advantageous with the embodiment of FIGS. 6 and 7 and the described modifications thereof. In such constructions, the differential gearing mechanisms of a frame of spindles may be disposed adjacent the end of the frame at which the supply and take up beams are located, and the one or more tension sensitive means connected to the differential gearing mechanisms will engage the strand (1 and/or the cord 0, as the case may be, in zones thereof adjacent the supply beam and/or the common take up beam.

What is claimed is:

1. Apparatus for twisting together two strands to form a plied strand, comprising a source of supply of a first strand, a source of supply of a second strand, means to rotate the second strand in a balloon about the source of supply of the first strand, a first means to feed the first strand at a predetermined rate of speed toward a plying point at the discharge end of the balloon, a second means to feed the second strand toward the balloon at substantially said predetermined rate of speed from a zone thereof which is under tension and in which it travels toward the second feeding means, said tension being appreciably less than that of the second strand in the balloon, and a third means for feeding the plied strand to withdraw it under tension at a variable speed from the plying point, the portions of said first and second strands extending from their respective sources of supply to the plying point and the portion of said plied strand extending from the plying point to the means for feeding the plied strand forming a strand system, changes in tension in said zone of the second strand being reflected in changes in the rate of feeding of the second strand toward the balloon by the second feeding means, means for driving the third feeding means, tension sensitive means responsive to variations in the tension of the second strand approaching the balloon, and means responsive to the tension sensitive means for varying the third feeding means.

2. Apparatus as claimed in claim 1, wherein said zone of the second strand extends to the second feeding means, the tension sensitive means comprises a rotatable member engaging said second strand in said zone thereof in a torque transmitting relationship, and the means responsive to the tension sensitive means is operatively connected between the rotatable member and the third feeding means so as to control the speed at which the third feeding means feeds the plied strand.

3. Apparatus as claimed in claim 2, wherein the third feeding means is a capstan, the means for driving the third feeding means comprises a variable speed driving mechanism having a first driving shaft, means for driving the first shaft at constant speed, a second shaft driven by the first shaft and drivingly connected to the capstan, and variable speed driving means interposed between and drivingly connecting the first and second shafts for selectively varying the driving ratio between the first and second shafts, and wherein the means responsive to the tension sensitive means is connected to the variable speed driving mechanism so as to control the speed of drive therethrough.

4. Apparatus according to claim 1, comprising an apex guide for the balloon, a driven fiyer for rotating the balloon, and an auxiliary fiyer engaging the balloon adjacent the apex guide so that the short balloon formed between the apex guide and the auxiliary fiyer always rotates in the first quadrant.

5. Apparatus according to claim 1, wherein the means responsive to the tension sensitive means varies the third feeding means so as to increase the speed of feeding of the plied strand by the third feeding means when the tension of said zone of the second strand decreases and to decrease the speed of feeding of the plied strand by the third feeding means when the tension of said zone of the second strand increases.

6. Apparatus for producing a plurality of plied strands simultaneously, said apparatus having a plurality of strand plying, balloon forming spindles, each spindle including means to support a supply of a first strand and a first means for advancing the first strand from its source of supply at a predetermined rate of speed to the plying point of the spindle at the discharge end of the balloon, a common supply. for a plurality of second strands, a second means for feeding each of the second strands from said common supply at substantially said predetermined rate of speed from a zone thereof which is under tension and in which it travels toward the second feeding means, the tension of the second strand in said zone being appreciably less than that of the balloon, said second means feeding the second strand to its respective plying spindle past the supply of first strand at such spindle and to the plying point of such spindle, changes in tension in said zone of the second strand being reflected in changes in the rate of feeding of the second strand toward the balloon by the second feeding means, means to rotate the portion of the second strand passing the source of supply of the first strand as the said balloon about the source of supply of the first strand so as to ply the two strands advancing toward each said plying point together to form a plied strand, individual, third feeding means for advancing each of said plied strands at variable speed under tension from their respectively plying points, and common take up' means for taking up all said plied Strands simultaneously, the portions of said first and second strands extending from their respective sources of supply to the plying point and the portion of said plied strand extending from the plying point to the common take up means forming a strand system, means for driving each of the third feeding means, tension sensitive means associated with each strand system responsive to variations in the tension of the said zone of the second strand, and means responsive to the tension sensitive means for varying the plied strand advancing speed of the respective third feeding means.

7. Apparatus as claimed in claim 6, wherein said zone I of the second strand extends to the second feeding means,

the common supply of the second strands is a beam, the common take up' means for the plied strands is a beam, and each of the individual, third feeding means for advancing the plied strands from the respective plying points is a capstan.

8. Apparatus as claimed in claim 7, comprising means for driving the common take up beam to subject the aggregate of the plied strands extending between the individual capstans for advancing the plied strands from their plying points andthe common take up beam to substantially constant tension.

9. Apparatus as claimed in claim 7, wherein each of the means for driving the respective third feeding means comprises a variable speed driving mechanism having a first, driving shaft, means for driving the first shaft at constant speed, a second shaft driven by the first shaft and drivingly connected to the capstan, and variable speed driving means interposed between and drivingly connecting the first and second shafts for selectively varying the driving ratio between the first and second shafts, and wherein the means responsive to the tension means is connected to the variable speed driving mechanism so as to control the speedfof drive therethrough.

10. Apparatus for twisting together two strands to form a plied strand, comprising a source of supply of a first strand, a source of supply of a second strand, means to rotate a zone of the second strand in a loop about the source of supply of the first strand, a first means to feed the first strand at a predetermined rate of speed toward a plying point, a second means to feed the second strand, at substantially said predetermined rate of speed toward the plying point, and a third, variable speed means for feeding the plyed' strand to withdraw it under tension fron the plying point, said first and second strands extending from their respective sources of supply to the plying point and said plied strand extending from/ the plying point to the third, variable speed means forming a strand system, a differential mechanism having a first, driving shaft and second and third differentially connected',shafts driven by the first shaft, means for driving the first shaft at constant speed, means drivingly connecting the third shaft to the third feeding means, tension sensitive means responsive to variation in the tension of at least one of the strands in said strand system for varying the speed of rotation of the third shaft of the differential mechanism, whereby to control the speed of advance of the plied strand from the plying point, said tension sensitive means including a rotatable member engaging said one strand of the strand system in a torque transmitting relationship, means operatively connecting the member to the second shaft so that rotation of the member controls the rotation of the second shaft, rotatable means driven at constant speed, and means yieldingly coupling said rotatable means to the second shaft.

11. Apparatus as claimed in claim 10, wherein the second means feeds the second strand into the loop, and said rotatable member is a body of revolution.

12. Apparatus as claimed in claim 11, wherein said means yieldingly coupling the rotatable means to the second shaft comprises a resilient member interposed between and having frictional driving engagement with the second shaft and the rotatable means which is driven at constant speed. i

13. Apparatus as claimed in claim 12, wherein the rotatable means which is driven at constant speed and the means yieldingly coupling said rotatable means to the second shaft are so constructed and arranged that in stable operation the portion of the body of revolution engaging the said one strand of the system rotates with a surface speed which is greater than the speed of the said one strand engaging it and which is somewhat different from the speed at which the constant speed rotatable means tends to drive it.

14. Apparatus as claimed in claim 13, wherein the rotatable means which is driven at constant Speed and the means yieldingly coupling the rotatable means to the second shaft are so constructed and arranged that in stable operation the rotatable means tends to drive the portion of the body of revolution engaging the said one strand of the system at a surface speed which is higher than its actual speed.

15. Apparatus as claimed in claim 14, wherein the body of revolution diverts the said one strand of the system into a salient zone as it travels therepast, and comprising means journalling on a fixed axis the rotatable means which is driven at constant speed, and means mounting the body of revolution and the second shaft for movement toward the said rotatable means and opposite the direction of convergence of the salient zone of said one strand, whereby increased tension in said Zone of said one strand causes the rotatable means increasingly to retard the second shaft and the body of revolution.

16. Apparatus as claimed in claim 11, comprising a take up means for taking up the plied strand from the third feeding means.

17. Apparatus as claimed in claim 16, comprising means for subjecting the second strand in the zone thereof approaching the second feeding means to substantially constant tension.

18. Apparatus as claimed in claim 17, wherein the said tension sensitive means engages and is responsive to variations in tension in the zone of the second strand approaching the second feeding means.

19. Apparatus as claimed in claim 17, wherein the tension sensitive means engages and is responsive to variations in tension in the zone of the plied strand which extends between the third feeding means and the take up means.

20. Apparatus as claimed in claim 17, wherein the tension sensitive means includes means engaging and responsive to variations in tension in the Zone of the second strand approaching the second feeding means, and means engaging and responsive to variations in tension in the zone of the plied strand which extends between the third feeding means and the take up means.

21. Apparatus as claimed in claim 20, wherein the tension sensitive means includes means engaging and responsive to variations in tension in the zone-of the second strand which extends between the second feeding means and the-plying point.

22. Apparatus for twisting together two strands to form a plied strand, comprising a source of supply of a first strand, a source of supply of a second strand, means to rotate a zone of the second strand in a balloon about the source of supply of the first strand, said balloon being a single balloon which spins below the bulge thereof, a first means to feed the first strand at a predetermined rate of speed towards .a plying point at the discharge end of the balloon, a second means to feed the second strand toward the balloon at substantially said predetermined rate of speed from a zone thereof which is under tension and in which it travels toward the second feeding means, said tension being appreciably less than that of the second strand in the balloon, and a third means for feeding the plied strand to withdraw it under tension at a variable speed from the plying point, means for taking up the plied strand from the third feeding means, the portions of said first and second strands extending from their respective sources of supply to the plying point and the portion of said plied strand extending from the plying point to the means for taking up the plied strand forming a strand system, said second feeding means impositively engaging the second strand, changes in tension in said zone of the second strand being reflected in changes in the rate of feeding of the second strand toward the balloon by the second feeding means, means for driving the third feeding means, tension sensitive means responsive to variations in the tension of said zone of the second strand, and means responsive to the tension sensitive means for varying the third feeding means so as to increase the speed of feeding of the plied strand by the third feeding means when the tension of said zone of the second strand decreases and to decrease the speed of feeding of the plied strand by the third feeding means when the tension of said zone of the second strand increases.

23. Apparatus as claimed in claim 22, wherein said Zone of the second strand extends to the second feeding means, the tension sensitive means comprises a rotatable member engaging said second strand in said zone thereof in a torque transmitting relationship, and the means responsive to the tension sensitive means is operatively connected between the rotatable member and the third feeding means so as to control the speed at which the third feeding means feeds the plied strand.

24. Apparatus as claimed in claim 23, wherein the third feeding means is a capstan, each of the means for driving the respective third feeding means comprises a variable speed driving mechanism having a first, driving shaft,

means for driving the first shaft at constant speed, a second shaft driven by the first shaft and drivingly connected to the capstan, and variable speed driving means interposed between and drivingly connecting the first and second shafts for selectively varying the driving ratio between the first and second shafts, and wherein the means responsive to the tension sensitive means is connected to the variable speed driving mechanism so as to control the speed of drive therethrough,

25. Apparatus for producing a plurality of plied strands simultaneouly, said apparatus having a plurality of strand lying, balloon forming spindles, each of said balloons being a single balloon which spins below the bulge thereof, each spindle including means to support a supply of a first strand and a first means for advancing the first strand from its source of supply at a predetermined rate of speed to the plying point of the spindle at the discharge end of the balloon, a common supply for a plurality of second strands, a second means for feeding each of the second strands from said common supply at substantially said predetermined rate of speed from a zone thereof which is under tension and in which it travels toward the second feeding means, the tension of the second strand in said zone being appreciably less than that of the balloon, said second means feeding the second strand to its respective plying spindle past the supply of first strand at such vspindle and to the plying point of such spindle, said second feeding means impositively engaging the second strand, changes in tension in said Zone of the second strand being reflected in changes in the rate of feeding of the second strand toward the balloon by the second feeding means, means to rotate the portion of the second strand passing the source of supply of the first strand as the said balloon about the source of supply of the first strand so as to ply the two strands advancing toward each said plying point together to form a plied strand, individual, third feeding means for advancing each of said plied strands at variable speed under tension from their respective plying points, and common take up means for taking up all said plied strands simultaneously, the portions of said first and second strands extending from their respective sources of supply to the plying point and the portion of said plied strand extending from the plying point to the common take up means forming a strand system, means for driving each of the third feeding means, tension sensitive means associated with each strand system responsive to variations in the tension of the said zone of the second strand, and means responsive to the tension sensitive means for varying the plied strand advancing speed of the respective third feeding means so as to in- 19 crease the plied strand advancing speed of the third feeding means when the tension of said zone of the second strand decreases and to decrease the plied strand advancing speed of the third feeding means when the tension of said zone of the second strand increases.

26. Apparatus as claimed in claim 25, wherein said zone of the second strand extends to the second feeding means, the common supply of the second strands is a beam, the common take up means for the plied strands is a beam, and each of the individual third feeding means for advancing the plied strands from the respective plying points is a capstan.

27. Apparatus as claimed in claim 26, comprising means for driving the common take up beam to subject the aggregate of the plied strands extending between the individual capstans for advancing the plied strands from their plying points and the common take up beam to substantially constant tension.

28. Apparatus as claimed in claim 26, wherein each of the means for driving the respective third feeding means comprises a variable speed driving mechanism having a first, driving shaft, means for driving the first shaft at constant speed, a second shaft driven by the first shaft and drivingly connected to the capstan, and variable speed driving means interposed between and drivingly connecting the first and second shafts for selectively varying the driving ratio between the first and second shafts, and wherein the means responsive to the tension sensitive means is connected to the variable speed driving mechanism so as to control the speed of drive therethrough.

29. In strand-twisting apparatus wherein a strand travels from a source of supply to a strand take-up means, in combination, mechanism for rotating the travelling strand in the form of a loop, mechanism for controlling the tension of the strand in the loop comprising a first means to feed the strand in a first run thereof toward the loop, a second means for withdrawing the strand in a second run thereof from the loop, one of said first and second means including means adapted to be driven at variable speed to vary the speed of feeding of the respective one of the runs of strand, a first, driving shaft and second and third differentially connected shafts driven by the first shaft, means for driving the first shaft at constant speed, means drivingly connecting the sound shaft to the variable speed means, and means responsive to variations in the tension of the other run of strand on the side of its feeding means remote from the loop for varying the speed of rotation of the third shaft.

30. Apparatus as claimed in claim 29, wherein the feeding means for said other run of strand engages it relatively impositively, and the tension in said other run of strand varies with changes of tension of the strand in the loop.

31. Apparatus as claimed in claim 29, wherein the means responsive to variations in the tension of a strand for varying the speed of rotation of the third shaft includes means engaging one of said two runs of strand outwardly of and spaced from the loop.

32. Apparatus as claimed in claim 29, wherein the apparatus twists two strands together to form a two-ply strand, and comprising a source of supply about which the loop of the first mentioned strand rotates, and a third means for feeding the second strand at substantially constant speed toward a plying point, and wherein the strand in the second strand run is plied strand.

33. Apparatus as claimed in claim 32, wherein the feeding means for said other run of strand engages it relatively impositively, and the tension in said other run of strand varies with changes of tension of the strand in the loop.

34. Apparatus as claimed in claim 33, wherein the means responsive to variations in the tension of a strand for varying the speed of rotation of the third shaft includes means engaging one of said two runs of strand outwardly of and spaced from the loop.

References Cited UNITED STATES PATENTS 2,811,012 10/1957 Klein 5758.83 XR 2,961,824 11/1960 Klein 5758.83 XR 3,153,893 10/1964 Vibber 5758.3 3,286,450 11/1966 Vibber 5758.3 3,290,873 12/1966 Vibber 5758.3 3,295,304 1/1967 Vibber 5758.3 3,307,342 3/1967 Vibber 5758.3

JOHN PETRAKES, Primary Examiner US. Cl. X.R. 

